The invention concerns a screw cap made from plastic according to the preamble of claim 1. These types of screw caps are manufactured in very large numbers by the injection molding process and are used to close off containers of the most varied kinds. Screw caps made of plastic have found an application mainly in the refreshment drinks branch, where the screw caps are screwed automatically onto the filled bottles on rapidly moving filling lines.
A problem with conventional screw caps occurs in that they must be screwed on with a definite application of torque, in order to ensure a sealed fit. Thereby, the screw movement is normally limited, since the bottle opening comes into contact with the base of the screw cap. The danger thus exists that the cap is screwed on with excessive torque, so that subsequently it can hardly be manually unscrewed. Overwinding of the threads can also occur in certain cases, since the bottle openings, especially in the case of glass bottles, can exhibit large variations of tolerance.